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Long-Term Results of Omitting Elective Level IB Irradiation in Node-Negative and Node-Positive Nasopharyngeal Carcinoma
Volume 99 Number 2S Supplement 2017
2874 Relapse Rates with Surgery Alone in HPV-Related Intermediate- and High-Risk-Group Oropharynx Squamous Cell Cancer: A Multi-Institutional Review D.M. Routman,1 R.K. Funk,1 K. Tangsriwong,2 A. Lin,3 K. Michael,4 J.J. Garcia,4 D.G. Stoddard,5 M.J. Eric,5 C.N. Day,6 Q. Zhai,7 K. Price,8 J.N. Lukens,9 S.M. Samuel,9 G.S. Weinstein,10 B. O’Malley,10 R.L. Foote,1 and D.J. Ma1; 1Department of Radiation Oncology, Mayo Clinic, Rochester, MN, 2RAJAVITHI HOSPITAL, BANGKOK, Thailand, 3 University of Pennsylvania, Philadelphia, PA, 4Division of Anatomic Pathology, Mayo Clinic, Rochester, MN, 5Department of Otolaryngology, Mayo Clinic, Rochester, MN, 6Department of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, 7Mayo Clinic, Jacksonville, FL, 8 Division of Medical Oncology, Mayo Clinic, Rochester, MN, 9Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, 10 Department of Otolaryngology University of Pennsylvania, Philadelphia, PA Purpose/Objective(s): Indications for adjuvant therapy including radiation therapy (RT) and chemotherapy after surgery for oropharyngeal squamous cell cancer (OPSCC) were defined prior to the predominance of human papilloma virus-related (HPV+) disease. Risk factors for relapse were likewise determined prior to the development of minimally invasive surgeries (MIS) such as transoral robotic surgery and transoral laser microsurgery. This study aimed to evaluate whether historic risk categories and indications for adjuvant therapy in the pre-HPV and pre-MIS era were associated with clinically significant relapse rates in HPV+ OPSCC patients undergoing MIS. Materials/Methods: A multi-institutional retrospective review of intermediate and high risk HPV+ OPSCC patients not receiving adjuvant therapy after MIS was performed. Perineural invasion (PNI), lymphovascular invasion (LVI), T3-T4, or >ZN2 disease were considered to be intermediate risk factors and extracapsular extension (ECE) or positive margins were considered to be high risk features based on established risk categories. Histopathologic review evaluated LVSI, PNI, and/or ECE for patients whose initial pathology reports did not comment specifically on the presence or absence of these parameters, when available. Univariate Cox Proportional Hazards models were used to assess clinical and pathologic risk factors for all relapses. Results: Median follow-up was 42.9 months. Among all 53 patients, the three year cumulative incidence of relapse was 26.0%. The three year cumulative incidence was 11.8% in the 37 intermediate risk patients and 52.4% in the 16 high risk patients. LVI was missing for 17 patients and PNI for 18 patients. On univariate analysis, only high risk status was significantly associated with an increased risk of relapse, HRZ3.9 (pZ0.018). The salvage rate for relapse was 77%, with 10 of 13 patients undergoing salvage therapy. With a median post-salvage follow-up of 20.6 months for these 10 patients, none of the patients had experienced a second relapse at time of last follow up. Conclusion: Risk category was associated with clinically significant relapse rates after MIS alone in HPV+ oropharyngeal cancer, comparable to historical data and traditional indications for adjuvant therapy for all oropharyngeal cancer. ECE had the highest association with relapse. Most intermediate risk category patients had 1 intermediate risk factor. Missing LVI and PNI data are limitations of this analysis. Like HPV- patients, HPV+ patients with traditional intermediate and high risk features should be offered adjuvant therapy. However, given the potential for salvage therapy and relatively low risk for relapse in intermediate risk patients, deescalation of adjuvant treatment remains an open consideration best answered by a prospective, randomized trial. Author Disclosure: D.M. Routman: None. R.K. Funk: None. K. Tangsriwong: None. A. Lin: Employee; Children’s Hospital of Philadelphia. Consultant; Elekta. K. Michael: None. J.J. Garcia: None. D.G. Stoddard: None. M.J. Eric: None. C.N. Day: None. Q. Zhai: None. K. Price: None. J.N. Lukens: None. S. Samuel: None. G.S. Weinstein: None. B. O’Malley: None. R.L. Foote: Employee; Mayo Clinic.
Poster Viewing E369 Consultant; Up to Date. responsible for clinical practice, research and education; Mayo Clinic. Responsible for the written board examination questions for head, neck and skin cancer.; ABR. D.J. Ma: None.
2875 Role of Adjuvant Radiotherapy for Resected Salivary Ductal Carcinoma S.J. Sandy, S. Suppiah, and J.R. Robbins; Medical College of Wisconsin, Department of Radiation Oncology, Milwaukee, WI Purpose/Objective(s): Salivary Ductal Carcinoma (SDC) is a rare, highly malignant tumor of the salivary glands. While current standard of care includes surgery followed by adjuvant radiotherapy, there are currently few prognostic data for the role of radiation therapy in the treatment of advanced stage SDC. This retrospective study sought to elucidate the impact of adjuvant radiotherapy (ART) in salivary ductal carcinoma on overall survival (OS) as well as define prognostic factors in this rare disease. Materials/Methods: A total of 495 patients diagnosed from 2004 to 2012 with salivary ductal carcinoma were identified from a query of the National Cancer Database (NCDB). Of these a total of 373 patients were identified who received surgery, without distant metastasis, and had data regarding adjuvant treatments and follow-up. Kaplan-Meier methods were used to evaluate OS. Univariate and multivariate Cox proportional hazards regression were used to identify factors associated with OS from time of surgery to death/last contact. Statistical analysis was performed using SPSS Version 24 (IBM Corp.). Results: In this cohort, the median age was 65 years old (range 22-90) with the majority being Caucasian (84%) with few comorbidities (CharlsonDeyo 0 in 84%). By stage, 17% stage I, 12% stage II, 15% stage III, 47% stage IV, and 8.8% were unknown. 268 patients (71.8%) received adjuvant radiation therapy. Patients who received ART were more likely to be younger (pZ0.005) and have positive margins (p<0.001). Median followup was 32 months. Using Cox multivariate regression analysis of all patients in the study, the factors impacting survival were age (HR 1.021, pZ0.018), sex (HR 1.658, pZ0.027), tumor size (HR 1.021, pZ0.002), 25 positive lymph nodes (HR 2.762, p < .001), more than 5 positive lymph nodes (HR 2.622, pZ0.001). Adjuvant RT was not associated with improved OS for the entire cohort. On multivariate analysis of patients with Stage 3 and 4 disease only, significant factors for overall survival were ART (HR .607, pZ0. 039), tumor size (HR 1.022, pZ0.001), 2-5 positive lymph nodes (HR Z 2.175, pZ0.027), and >5 positive lymph nodes (HR 2.177, pZ0.028). For these patients, the median overall survival was 29 months without ART and 49 months with ART (pZ0.003). Three-year survival was 46.1% without ART and 65.5% with ART. Conclusion: While ART did not statistically improve overall survival in stage 1-2 patients, multivariate analysis limited to stage 3-4 patients showed a statistically significant improvement in OS. ART should be considered in stage 3-4 patients following resection. In addition, important prognostic factors for this disease include age, sex, tumor size, and number of positive lymph nodes. Additional studies in this rare tumor are needed to confirm this result. Author Disclosure: S.J. Sandy: None. S. Suppiah: None. J.R. Robbins: Travel Expenses; Elekta.
2876 Long-Term Results of Omitting Elective Level IB Irradiation in Node-Negative and Node-Positive Nasopharyngeal Carcinoma N.N. Sanford,1 M.B. Lam,2 J.A. Adams,3 S.I. Goldberg,4 Y. Zhang,4,5 E.A. Weyman,4 P.M. Busse,4 N.J. Liebsch,4 and A.W. Chan4; 1Harvard Radiation Oncology Program, Boston, MA, 2Department of Radiation Oncology, Brigham and Women’s Hospital, Boston, MA, 3Massachusetts General Hospital- Harvard Medical School, Radiation Oncology, Boston, MA, 4Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, 5Department of Oncology, Xiangya Hospital of Central South University, Changsha, China
E370
International Journal of Radiation Oncology Biology Physics
Purpose/Objective(s): Although prior studies have shown that level IB involvement in nasopharyngeal carcinoma (NPC) is rare, many protocols still recommend elective nodal irradiation (ENI) of IB, which can lead to increased toxicities such as mucositis, xerostomia, laryngeal edema, and osteoradionecrosis. The purpose of this study was to evaluate our policy of withholding bilateral elective IB coverage, unless clinically indicated, in patients with node-negative and node-positive NPC. Materials/Methods: Between 1999 and 2014, 74 patients with NPC were treated with definitive RT. The nodal clinical target volume (CTV) included the bilateral retropharyngeal and level II-V nodes. Contralateral and ipsilateral level IB was omitted on node-negative and node-positive patients to decrease radiation dose to the submandibular glands, oral cavity, mandible, suprahyoid muscles, and larynx, unless there was involvement of IB and/or involvement of structures that drain to IB as the first echelon site. Clinical and treatment characteristics were: median age at diagnosis 51 years (range 14-78), male 76%, White 58%, Asian 24%, Stage III 30%, Stage IVA 49%, Stage IVB 10%. The T and N staging distributions were: T1 14%, T2 15%, T3 18%, T4 54%, N0 24%, N1 19%, N2 47%, N3 9%. The median delivered dose to the GTV was 70 Gy (range 69.96 e 76), to the CTV and upper neck nodes 60 Gy (range 44 e 66) and to lower neck nodes 54 Gy (range 44 e 69.96). Eight-two percent were treated with protons and 96% received chemotherapy including 24% induction and concurrent, 30% concurrent alone, and 38% concurrent and adjuvant. The primary endpoint, locoregional control, and secondary endpoints, including overall survival and disease free survival were estimated by the Kaplan-Meier method. Results: With a median follow-up time of 5.6 years, there were 3 patients with local recurrence alone and 1 patient with synchronous local and regional recurrence. All local recurrences occurred in the high-dose 70 Gy target volume. The one nodal failure was in a patient with persistent disease at the ipsilateral level II and retropharyngeal nodes previously treated to 70 Gy. There was no failure in IB in the entire cohort. The rates of 2and 5-year local control were 97.2% and 95.7% respectively, of regional control were 98.6% and 98.6% respectively and of overall survival were 91.8% and 83.8% respectively. Thirty-nine percent of patients had g-tube placement before or during radiation therapy. The median weight loss during treatment was 7.6 kg (range 0.2 e 16.1) and 5.4% had more than 15% weight loss. At 2 years, 2.7% of patients had grade 2 xerostomia and 2.7% of patients had osteoradionecrosis of the mandible. There was no grade 3 or higher xerostomia or osteoradionecrosis. Conclusion: ENI to ipsilateral and contralateral level IB for patients with NPC is unnecessary when there is no involvement of 1B or of areas draining to 1B. Author Disclosure: N.N. Sanford: None. M.B. Lam: None. J.A. Adams: None. S.I. Goldberg: None. Y. Zhang: None. E.A. Weyman: None. P.M. Busse: None. N.J. Liebsch: None. A.W. Chan: None.
irradiation. Since April 2013 through December 2016, 17 patients with Tis-T2 N0 M0 SCCA have been treated with interstitial brachytherapy. 14 patient patients were treated with definitive radiotherapy. 10 of those patients received brachytherapy has monotherapy, while 4 others received external beam radiotherapy followed by a brachytherapy boost. 1 patient received brachytherapy for a recurrence after prior external beam radiation and surgical salvage for recurrence. 2 patients received it as adjuvant therapy after primary surgical resection for known pathologic risk factor of PNI. Brachytherapy dose was 42.5-47.5 Gy in 10 fractions given BID over 1 week in the setting of definitive monotherapy, 17-24 Gy in 5-6 fractions given BID in the setting of a boost after external beam radiation and 35-36 Gy in 9-10 fractions given BID over 1 week in the setting of post-surgical adjuvant therapy for microscopic disease. Results: The median time to follow-up for this cohort is 18 months (3-38 months). The local control rate is 94.1%. There has been one local failure which was then salvaged with single agent Cetuximab. There has been one regional failure along the path of ipsilateral CN V3 which was then treated with chemoradiation. There have been no nodal failures. Conclusion: HDR Interstitial brachytherapy is an excellent radiotherapeutic option for early stage lip SCCA. It offers a very convenient alternative to patients with early stage disease allowing their treatment time to be condensed to 1 week in lieu of a 6-7 week course of external beam radiation. Author Disclosure: P. Sanghvi: Independent Contractor; iCAD. Speaker’s Bureau; iCAD. C.W. Williamson: None. P. Martin: None. D.W. Brown: Partnership; TreatSafely. J.P. Einck: Independent Contractor; American College of Radiation Oncology. Board Member, Advisor; Cure Cervical Cancer. oRG. D.J. Scanderbeg: Research Grant; Cianna Medical Inc. V. Moiseenko: None.
2877 HDR Interstitial Brachytherapy in the Management of Lip Malignancies P. Sanghvi,1 C.W. Williamson,1 P. Martin,2 D.W. Brown,3 J.P. Einck,1 D.J. Scanderbeg,4 and V. Moiseenko1; 1University of California, San Diego, La Jolla, CA, 2Kaiser Permanente, San Diego, CA, 3University of California at San Diego, La Jolla, CA, 4University of California, San Diego, La Jolla, CA, United States Purpose/Objective(s): Brachytherapy is an appealing alternative to external beam radiotherapy in the management of early stage primary lip cancers. Historically LDR brachytherapy and recent HDR brachytherapy has been shown to provide at least equivalent local control and improvement in the therapeutic ratio compared to external beam radiation. We report our department experience over the last 3 years. Materials/Methods: Since 2013, HDR interstitial brachytherapy has been offered to patients with squamous cell carcinoma involving the non-hair bearing lip. It has been offered as monotherapy in the definitive setting for early stage lesions as well as adjuvant therapy in post-operative patients with known pathologic risk factors (+ margins, + PNI) or as a boost after external beam radiotherapy in locally advanced patients requiring nodal
2878 N3 (‡6 cm) Locally Advanced Head and Neck Squamous Cell Carcinoma: A Monocentric Study of 105 Patients S. Sellami,1 F. Lucia,1 Y. Gobel,2 R. Abgral,3 D. Gouders,4 O. Sparfel,5 O. Miranda,1,4 O. Pradier,1 and U. Schick1; 1Radiation Oncology Department, Oncology Institute of Western Brittany, University Hospital., BREST, France, 2Department of Head and Neck Surgery and Otorhinolaryngology Department, Oncology Institute of Western Brittany, University Hospital., BREST, France, 3Nuclear Medecine Department, Oncology Institute of Western Brittany, University Hospital., BREST, France, 4Radiation Oncology Department, Oncology Institute of Western Brittany, Hospital Intercommunal de Cornouaille., QUIMPER, France, 5 Department of Head and Neck Surgery and Otorhinolaryngology Department, Oncology Institute of Western Brittany, Hospital Intercommunal de Cornouaille., QUIMPER, France Purpose/Objective(s): N3 (6 cm) locally advanced head and neck squamous cell carcinoma (LAHNSCC) is a rare malignancy. We aimed to assess the clinical profile, outcome and prognostic factors in N3 LAHNSCC. Materials/Methods: From 01/2005 to 12/2016, 105 patients with nonmetastatic N3 LAHNSCC treated with surgery (S) and/or radiotherapy (RT), with or without chemotherapy (CT) with curative intent were included. The primary tumor sites were the oral cavity (nZ8), the oropharynx (nZ 40), the hypopharynx (nZ34), and the larynx (nZ 2). Eight patients had 2 synchronous tumors and 13 a cancer of unknown primary origin (CUP). Median age was 60.2 months (range, 40.4 e 85.9) and median follow up of surviving patients was 43.7 months (range, 6-112). Sixty-nine patients were treated with RT CT and 36 with S, completed by RT CT in 31 of them. Positronemission tomography-computed tomography (PET-CT) guided surveillance after RT CT, as opposed to planned neck-dissection (ND), was standard. Impact of clinical variables (gender, age, body mass index (BMI), ECOG performance status (PS), tobacco consumption, primary site, T stage, maximum nodal size, hemoglobin value (Hb) and type of initial treatment) on overall survival (OS) and locoregional control (LRC) was analyzed by uni- and multivariate analysis.
2874 Relapse Rates with Surgery Alone in HPV-Related Intermediate- and High-Risk-Group Oropharynx Squamous Cell Cancer: A Multi-Institutional Review D.M. Routman,1 R.K. Funk,1 K. Tangsriwong,2 A. Lin,3 K. Michael,4 J.J. Garcia,4 D.G. Stoddard,5 M.J. Eric,5 C.N. Day,6 Q. Zhai,7 K. Price,8 J.N. Lukens,9 S.M. Samuel,9 G.S. Weinstein,10 B. O’Malley,10 R.L. Foote,1 and D.J. Ma1; 1Department of Radiation Oncology, Mayo Clinic, Rochester, MN, 2RAJAVITHI HOSPITAL, BANGKOK, Thailand, 3 University of Pennsylvania, Philadelphia, PA, 4Division of Anatomic Pathology, Mayo Clinic, Rochester, MN, 5Department of Otolaryngology, Mayo Clinic, Rochester, MN, 6Department of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, 7Mayo Clinic, Jacksonville, FL, 8 Division of Medical Oncology, Mayo Clinic, Rochester, MN, 9Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, 10 Department of Otolaryngology University of Pennsylvania, Philadelphia, PA Purpose/Objective(s): Indications for adjuvant therapy including radiation therapy (RT) and chemotherapy after surgery for oropharyngeal squamous cell cancer (OPSCC) were defined prior to the predominance of human papilloma virus-related (HPV+) disease. Risk factors for relapse were likewise determined prior to the development of minimally invasive surgeries (MIS) such as transoral robotic surgery and transoral laser microsurgery. This study aimed to evaluate whether historic risk categories and indications for adjuvant therapy in the pre-HPV and pre-MIS era were associated with clinically significant relapse rates in HPV+ OPSCC patients undergoing MIS. Materials/Methods: A multi-institutional retrospective review of intermediate and high risk HPV+ OPSCC patients not receiving adjuvant therapy after MIS was performed. Perineural invasion (PNI), lymphovascular invasion (LVI), T3-T4, or >ZN2 disease were considered to be intermediate risk factors and extracapsular extension (ECE) or positive margins were considered to be high risk features based on established risk categories. Histopathologic review evaluated LVSI, PNI, and/or ECE for patients whose initial pathology reports did not comment specifically on the presence or absence of these parameters, when available. Univariate Cox Proportional Hazards models were used to assess clinical and pathologic risk factors for all relapses. Results: Median follow-up was 42.9 months. Among all 53 patients, the three year cumulative incidence of relapse was 26.0%. The three year cumulative incidence was 11.8% in the 37 intermediate risk patients and 52.4% in the 16 high risk patients. LVI was missing for 17 patients and PNI for 18 patients. On univariate analysis, only high risk status was significantly associated with an increased risk of relapse, HRZ3.9 (pZ0.018). The salvage rate for relapse was 77%, with 10 of 13 patients undergoing salvage therapy. With a median post-salvage follow-up of 20.6 months for these 10 patients, none of the patients had experienced a second relapse at time of last follow up. Conclusion: Risk category was associated with clinically significant relapse rates after MIS alone in HPV+ oropharyngeal cancer, comparable to historical data and traditional indications for adjuvant therapy for all oropharyngeal cancer. ECE had the highest association with relapse. Most intermediate risk category patients had 1 intermediate risk factor. Missing LVI and PNI data are limitations of this analysis. Like HPV- patients, HPV+ patients with traditional intermediate and high risk features should be offered adjuvant therapy. However, given the potential for salvage therapy and relatively low risk for relapse in intermediate risk patients, deescalation of adjuvant treatment remains an open consideration best answered by a prospective, randomized trial. Author Disclosure: D.M. Routman: None. R.K. Funk: None. K. Tangsriwong: None. A. Lin: Employee; Children’s Hospital of Philadelphia. Consultant; Elekta. K. Michael: None. J.J. Garcia: None. D.G. Stoddard: None. M.J. Eric: None. C.N. Day: None. Q. Zhai: None. K. Price: None. J.N. Lukens: None. S. Samuel: None. G.S. Weinstein: None. B. O’Malley: None. R.L. Foote: Employee; Mayo Clinic.
Poster Viewing E369 Consultant; Up to Date. responsible for clinical practice, research and education; Mayo Clinic. Responsible for the written board examination questions for head, neck and skin cancer.; ABR. D.J. Ma: None.
2875 Role of Adjuvant Radiotherapy for Resected Salivary Ductal Carcinoma S.J. Sandy, S. Suppiah, and J.R. Robbins; Medical College of Wisconsin, Department of Radiation Oncology, Milwaukee, WI Purpose/Objective(s): Salivary Ductal Carcinoma (SDC) is a rare, highly malignant tumor of the salivary glands. While current standard of care includes surgery followed by adjuvant radiotherapy, there are currently few prognostic data for the role of radiation therapy in the treatment of advanced stage SDC. This retrospective study sought to elucidate the impact of adjuvant radiotherapy (ART) in salivary ductal carcinoma on overall survival (OS) as well as define prognostic factors in this rare disease. Materials/Methods: A total of 495 patients diagnosed from 2004 to 2012 with salivary ductal carcinoma were identified from a query of the National Cancer Database (NCDB). Of these a total of 373 patients were identified who received surgery, without distant metastasis, and had data regarding adjuvant treatments and follow-up. Kaplan-Meier methods were used to evaluate OS. Univariate and multivariate Cox proportional hazards regression were used to identify factors associated with OS from time of surgery to death/last contact. Statistical analysis was performed using SPSS Version 24 (IBM Corp.). Results: In this cohort, the median age was 65 years old (range 22-90) with the majority being Caucasian (84%) with few comorbidities (CharlsonDeyo 0 in 84%). By stage, 17% stage I, 12% stage II, 15% stage III, 47% stage IV, and 8.8% were unknown. 268 patients (71.8%) received adjuvant radiation therapy. Patients who received ART were more likely to be younger (pZ0.005) and have positive margins (p<0.001). Median followup was 32 months. Using Cox multivariate regression analysis of all patients in the study, the factors impacting survival were age (HR 1.021, pZ0.018), sex (HR 1.658, pZ0.027), tumor size (HR 1.021, pZ0.002), 25 positive lymph nodes (HR 2.762, p < .001), more than 5 positive lymph nodes (HR 2.622, pZ0.001). Adjuvant RT was not associated with improved OS for the entire cohort. On multivariate analysis of patients with Stage 3 and 4 disease only, significant factors for overall survival were ART (HR .607, pZ0. 039), tumor size (HR 1.022, pZ0.001), 2-5 positive lymph nodes (HR Z 2.175, pZ0.027), and >5 positive lymph nodes (HR 2.177, pZ0.028). For these patients, the median overall survival was 29 months without ART and 49 months with ART (pZ0.003). Three-year survival was 46.1% without ART and 65.5% with ART. Conclusion: While ART did not statistically improve overall survival in stage 1-2 patients, multivariate analysis limited to stage 3-4 patients showed a statistically significant improvement in OS. ART should be considered in stage 3-4 patients following resection. In addition, important prognostic factors for this disease include age, sex, tumor size, and number of positive lymph nodes. Additional studies in this rare tumor are needed to confirm this result. Author Disclosure: S.J. Sandy: None. S. Suppiah: None. J.R. Robbins: Travel Expenses; Elekta.
2876 Long-Term Results of Omitting Elective Level IB Irradiation in Node-Negative and Node-Positive Nasopharyngeal Carcinoma N.N. Sanford,1 M.B. Lam,2 J.A. Adams,3 S.I. Goldberg,4 Y. Zhang,4,5 E.A. Weyman,4 P.M. Busse,4 N.J. Liebsch,4 and A.W. Chan4; 1Harvard Radiation Oncology Program, Boston, MA, 2Department of Radiation Oncology, Brigham and Women’s Hospital, Boston, MA, 3Massachusetts General Hospital- Harvard Medical School, Radiation Oncology, Boston, MA, 4Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, 5Department of Oncology, Xiangya Hospital of Central South University, Changsha, China
E370
International Journal of Radiation Oncology Biology Physics
Purpose/Objective(s): Although prior studies have shown that level IB involvement in nasopharyngeal carcinoma (NPC) is rare, many protocols still recommend elective nodal irradiation (ENI) of IB, which can lead to increased toxicities such as mucositis, xerostomia, laryngeal edema, and osteoradionecrosis. The purpose of this study was to evaluate our policy of withholding bilateral elective IB coverage, unless clinically indicated, in patients with node-negative and node-positive NPC. Materials/Methods: Between 1999 and 2014, 74 patients with NPC were treated with definitive RT. The nodal clinical target volume (CTV) included the bilateral retropharyngeal and level II-V nodes. Contralateral and ipsilateral level IB was omitted on node-negative and node-positive patients to decrease radiation dose to the submandibular glands, oral cavity, mandible, suprahyoid muscles, and larynx, unless there was involvement of IB and/or involvement of structures that drain to IB as the first echelon site. Clinical and treatment characteristics were: median age at diagnosis 51 years (range 14-78), male 76%, White 58%, Asian 24%, Stage III 30%, Stage IVA 49%, Stage IVB 10%. The T and N staging distributions were: T1 14%, T2 15%, T3 18%, T4 54%, N0 24%, N1 19%, N2 47%, N3 9%. The median delivered dose to the GTV was 70 Gy (range 69.96 e 76), to the CTV and upper neck nodes 60 Gy (range 44 e 66) and to lower neck nodes 54 Gy (range 44 e 69.96). Eight-two percent were treated with protons and 96% received chemotherapy including 24% induction and concurrent, 30% concurrent alone, and 38% concurrent and adjuvant. The primary endpoint, locoregional control, and secondary endpoints, including overall survival and disease free survival were estimated by the Kaplan-Meier method. Results: With a median follow-up time of 5.6 years, there were 3 patients with local recurrence alone and 1 patient with synchronous local and regional recurrence. All local recurrences occurred in the high-dose 70 Gy target volume. The one nodal failure was in a patient with persistent disease at the ipsilateral level II and retropharyngeal nodes previously treated to 70 Gy. There was no failure in IB in the entire cohort. The rates of 2and 5-year local control were 97.2% and 95.7% respectively, of regional control were 98.6% and 98.6% respectively and of overall survival were 91.8% and 83.8% respectively. Thirty-nine percent of patients had g-tube placement before or during radiation therapy. The median weight loss during treatment was 7.6 kg (range 0.2 e 16.1) and 5.4% had more than 15% weight loss. At 2 years, 2.7% of patients had grade 2 xerostomia and 2.7% of patients had osteoradionecrosis of the mandible. There was no grade 3 or higher xerostomia or osteoradionecrosis. Conclusion: ENI to ipsilateral and contralateral level IB for patients with NPC is unnecessary when there is no involvement of 1B or of areas draining to 1B. Author Disclosure: N.N. Sanford: None. M.B. Lam: None. J.A. Adams: None. S.I. Goldberg: None. Y. Zhang: None. E.A. Weyman: None. P.M. Busse: None. N.J. Liebsch: None. A.W. Chan: None.
irradiation. Since April 2013 through December 2016, 17 patients with Tis-T2 N0 M0 SCCA have been treated with interstitial brachytherapy. 14 patient patients were treated with definitive radiotherapy. 10 of those patients received brachytherapy has monotherapy, while 4 others received external beam radiotherapy followed by a brachytherapy boost. 1 patient received brachytherapy for a recurrence after prior external beam radiation and surgical salvage for recurrence. 2 patients received it as adjuvant therapy after primary surgical resection for known pathologic risk factor of PNI. Brachytherapy dose was 42.5-47.5 Gy in 10 fractions given BID over 1 week in the setting of definitive monotherapy, 17-24 Gy in 5-6 fractions given BID in the setting of a boost after external beam radiation and 35-36 Gy in 9-10 fractions given BID over 1 week in the setting of post-surgical adjuvant therapy for microscopic disease. Results: The median time to follow-up for this cohort is 18 months (3-38 months). The local control rate is 94.1%. There has been one local failure which was then salvaged with single agent Cetuximab. There has been one regional failure along the path of ipsilateral CN V3 which was then treated with chemoradiation. There have been no nodal failures. Conclusion: HDR Interstitial brachytherapy is an excellent radiotherapeutic option for early stage lip SCCA. It offers a very convenient alternative to patients with early stage disease allowing their treatment time to be condensed to 1 week in lieu of a 6-7 week course of external beam radiation. Author Disclosure: P. Sanghvi: Independent Contractor; iCAD. Speaker’s Bureau; iCAD. C.W. Williamson: None. P. Martin: None. D.W. Brown: Partnership; TreatSafely. J.P. Einck: Independent Contractor; American College of Radiation Oncology. Board Member, Advisor; Cure Cervical Cancer. oRG. D.J. Scanderbeg: Research Grant; Cianna Medical Inc. V. Moiseenko: None.
2877 HDR Interstitial Brachytherapy in the Management of Lip Malignancies P. Sanghvi,1 C.W. Williamson,1 P. Martin,2 D.W. Brown,3 J.P. Einck,1 D.J. Scanderbeg,4 and V. Moiseenko1; 1University of California, San Diego, La Jolla, CA, 2Kaiser Permanente, San Diego, CA, 3University of California at San Diego, La Jolla, CA, 4University of California, San Diego, La Jolla, CA, United States Purpose/Objective(s): Brachytherapy is an appealing alternative to external beam radiotherapy in the management of early stage primary lip cancers. Historically LDR brachytherapy and recent HDR brachytherapy has been shown to provide at least equivalent local control and improvement in the therapeutic ratio compared to external beam radiation. We report our department experience over the last 3 years. Materials/Methods: Since 2013, HDR interstitial brachytherapy has been offered to patients with squamous cell carcinoma involving the non-hair bearing lip. It has been offered as monotherapy in the definitive setting for early stage lesions as well as adjuvant therapy in post-operative patients with known pathologic risk factors (+ margins, + PNI) or as a boost after external beam radiotherapy in locally advanced patients requiring nodal
2878 N3 (‡6 cm) Locally Advanced Head and Neck Squamous Cell Carcinoma: A Monocentric Study of 105 Patients S. Sellami,1 F. Lucia,1 Y. Gobel,2 R. Abgral,3 D. Gouders,4 O. Sparfel,5 O. Miranda,1,4 O. Pradier,1 and U. Schick1; 1Radiation Oncology Department, Oncology Institute of Western Brittany, University Hospital., BREST, France, 2Department of Head and Neck Surgery and Otorhinolaryngology Department, Oncology Institute of Western Brittany, University Hospital., BREST, France, 3Nuclear Medecine Department, Oncology Institute of Western Brittany, University Hospital., BREST, France, 4Radiation Oncology Department, Oncology Institute of Western Brittany, Hospital Intercommunal de Cornouaille., QUIMPER, France, 5 Department of Head and Neck Surgery and Otorhinolaryngology Department, Oncology Institute of Western Brittany, Hospital Intercommunal de Cornouaille., QUIMPER, France Purpose/Objective(s): N3 (6 cm) locally advanced head and neck squamous cell carcinoma (LAHNSCC) is a rare malignancy. We aimed to assess the clinical profile, outcome and prognostic factors in N3 LAHNSCC. Materials/Methods: From 01/2005 to 12/2016, 105 patients with nonmetastatic N3 LAHNSCC treated with surgery (S) and/or radiotherapy (RT), with or without chemotherapy (CT) with curative intent were included. The primary tumor sites were the oral cavity (nZ8), the oropharynx (nZ 40), the hypopharynx (nZ34), and the larynx (nZ 2). Eight patients had 2 synchronous tumors and 13 a cancer of unknown primary origin (CUP). Median age was 60.2 months (range, 40.4 e 85.9) and median follow up of surviving patients was 43.7 months (range, 6-112). Sixty-nine patients were treated with RT CT and 36 with S, completed by RT CT in 31 of them. Positronemission tomography-computed tomography (PET-CT) guided surveillance after RT CT, as opposed to planned neck-dissection (ND), was standard. Impact of clinical variables (gender, age, body mass index (BMI), ECOG performance status (PS), tobacco consumption, primary site, T stage, maximum nodal size, hemoglobin value (Hb) and type of initial treatment) on overall survival (OS) and locoregional control (LRC) was analyzed by uni- and multivariate analysis.